Drill press



Dec. 25, 1951 R. H. ALLEN 2,579,459

DRILL PRESS Filed June 24, 1946 1 6 Sheets-Sheet .2

R. H. ALLE-N' 2,579,459

Dec. 25, 1951 DRILL PRESS 6 Sheets-Sheet 5 Filed June 24, 1946 Dec. 25,-1951 v R. H. ALLEN DRILL PRESS Filed June 24,

6 "Sheets-Shae; 4

Dec. 25, 1951 R ALLEN 2,579,459

DRILL PRESS Filed June 24, 1946 6 Sheets-Sheet 5- H; ALLEN Dec. 25; 1951 DRILL PRESS I 6 Sheets-Sheet 6 Filed June 24, 1946 Patented Dec. 25, 1951 emu. PRESS.

Robert-Ht Allen, Barre, Mass, assignonto Chas.- 'G. Allen 60., Barre, Mass, acorporation of Massachusetts [A lic nse a4, 1946, srial'noicisszc I Glaims. (Cl. 77 -323) This invention, pertains tofdrill'presses; and more-particularly to an' electrically control-led press of the repetitious step-dri-1l-;type.

In drilling deep sections, it necessary to periodically remove the, drill" from; the 'worlr piece fill cooling of both thedriiland Work piece and also for chip removal. Depending upon the depth of drill,, it may be necessary to remove, the tool from the work by elevation of the quill arnumber of times during. the drilling of 4 one, piece.

Such repetitious elevations of the quill have heretofore been manually controlled: or in some instances hydraulicallycontrolled; In, manual control the, attendance ofthe operator is con-- stantly needed, whichrequires an: operator;- for each spindle used. In using the hydraulic con,- trol, much additional equipment is needemrasjfor example the pump, the hydraulic pressure :lines, vand the pressureoperated'control mechanism. Such additional equipmentin'volves, a considerable increaseirr cost of the drill plus rather frequent, maintenanceoperations,

In the present'machine'the removal, and; re-' entry of thedrili into'the workpiece is} electrically controlled with the 'additiontof relatively few pieces of equipment to that normally found upon a standardmanuai drill press; Not only-is the resulting machine simplified in construction,

but it. is more eificient and less likely'to get out of repair. Furthermore, the control equipment is substantially self'contai'ned and can be in- 'corporated in the drillpress without a complete redesign of' the unit.

Thus, the, obi'ect of the present. invention. is to improve the construction as well as the means and mode of operation of step-drill presses whereby'they may not only be more economically and easily assembled 'but'r th jparts thereof will be more accessible for inspection and replacement, and be less likely to get. outiof repai Or adjustment.

A further object of, the invention is to provide a. substantially self-contained A further object. ofthe invention is toprovide a, device of the character described-in which the reciprocation of .the quill and spindle is fully automatic, including means for controlling movement of the quill uponapproach' of the drill tool pletethrongh-a predetermined number of cycles 15 control unit wherein the parts are so arranged, as to minimize adjustment difiiculties.

the completedrilling operation, and -return to res tawai-ting removal of the operated work piece,

A further object of theinveI-i-tion is to provide adevice of thecharacter described having the advantageous structural features and inherent meritorious characteristics and mode of operation hereinafter set forth.'

With the above primary and other incidental objectsi'n view as will more fully appeariin the specification, the invention intended to be protected byLetters Patent consistsof-the features of construction; the parts and combinations thereof, and the mode of operation, or their equivalents, as hereinafter describedor illustratedin the accompanying drawings,

In the drawings; wherein are illustrated preferred but obviously not necessarily the only forms ofembodiment of the invention,

' Fig. I is a-perspective viewof a drill press embodying thepresent invention.

Fig; 2' is afront elevation partlyin "section of the'control mechanism.- a

Fig. 3 is a side view partly insection of the control mechanism looking from the ri'ght" of Fig; 2'. V

Fig 4 is a side view-part1y section of the control mechanism looking 'from the:- left" of Fig. 2.'

Fig. 5 is a" sectional view on--line 5'-5 of Figs. 3 and'e. v

Fig. 6" is asectional view" on line 6-'-o"of-Fig. 5.

Fig. '7' is a detail view partly in section ofthe overrunning clutch and one of the drive means therefor. 7

Fig. 8" is an enlarged detailview of the ratchet sections; 7

' Fig. 9 is an enlarged sectional-view of' one of the guiderods. I

Fig. 10' is a schematic wiring diagram of the electrical control system. 7

Like partS' Ie-indicated' by similarireference characters throughout the several views.

In general, the present invention relates to drilling deep holes Where the depth tobe drilled is in the neighborhood 0? ten to forty times. the diameter of the tool and where thematerial is such that after a tool penetration of one ortwo diameters, the tool*must be completely withdrawn from thehole' te-clear chips and to permit coolant to enter the partly drilled hole The present structure provides automatic fast travel of the toolto the work piece; automatic engagement of the 'regulated toolfeed just before th'e toolengages the work, and automatic-fast retraction of the tool to its starting point'a-f-ter the obtained, after which the tool is retracted under fast travel motion to its original starting point and remains there until a new cycle ofoperations is begun by momentarily manually closing an electrical contact, after putting a new work piece into the fixture.

The number of operations in each cycle and the depth of penetratioriduring each operation is definitely and accurately predetermined by settings which remain constant during extended periods of operation. Furthermore, the particular settings can be accurately duplicated at any later time should thesame type of work; again be-required. v r v u Referring to the drawings, there is mounted upon thebase I the usual lower column or housing 2, upon which the table 3 is vertically adjustable along the ways or guides 4. Carried by the lower column 2 is a top column 5 upon which the spindle actuating means and feed control units are supported. Mounted in relatively fixed position upon the back of the top column is a motor 6, which through the step pulley 1 and belt 8 actuates the drill spindle and associated mechanism.

Contained within the housing 9 fixedly supported upon the front of the top column 5 is a change speed mechanism, comprising a group of I optionally engageable gears which provide a series of relatively high spindle speeds, or through the use of a back gear arrangement provides a series of relatively lowf spindle speeds.- The input shaft of the change speed mechanismis driven by the belt 8 through thestep pulleyIEi.

The output of the change speed mechanisn is delivered to the drill spindle I I through a spline connection within the housing which permits continuous rotation of the spindle II, although invarious positions of verticaladjustment.

.A secondary change speedmechanism is enclosed Within the housing I2, the input for which is taken from the principal change speed mechanism 9. The speed of the output shaft I3 of the secondary change speed mechanism I2 is adjustable bya ch nge of gears therein, but always has a definite predetermined ratio in relation to the speed of the spindle II. The shaft I3 controls, through appropriate mechanism to be later described, the rate of down feed of the drill spindle I I. The rate of feed of the spindle I I in relation to its speed of rotation can be accurately determined and preset by this mechanism. Such setting can be maintained throughout extended periods of operations or duplicated at some later date.

Immediately below the change speed mechanisms 9 and I2 is a housing I4 within which the automatic control mechanism is enclosed. This housing is integral with an arm I5 adjustably supported upon the top column 5 by guides or ways IS. The arm I5 further serves as support for the quill II, within which the drill spindle I I rotates. V

The quill I1 is vertically adjustable relative to its supporting arm I5, providing vertical movement to the drill spindle II which is vertically fixed relative thereto. Downward movement of the quill I'I governs the rate of feed of the drill spindle'II into the work piece. Upward movement of the quill retracts the drill spindle from the work ;piece preparatory to'the next drilling operation.

The rate of downward movement of the quill I! or rate of feed of the drill spindle II is controlled by the secondary change speed mechanism' I2 through rotation of its output shaft I3. Slidingly engaged upon the lower end of the shaft I3 by means'of a spline I3 is a worm I8 fixedly supported in a housing I9 projecting from the side of the vertically adjustable arm I5. The spli'ne'd connection of the worm I8 with the shaft I3wpermits continuous driving engagement therebetween regardless of the vertical position of the arm I5 and associated-housing I9. Meshing with the worm I8 is ,a worm gear 2fl which comprises one element of an overrunning, or free-wheeling" clutchunitZL i T The clutch 2i 7 with its axis transversely disposecl'relative to the shaft"l3is supported within the housing I9.upon a feed pinions'ha'ft 22. Supported for. independent rotation upon a projection 23 of the feed pinion shaft 22 is the operating disc' 24 of theclut'ch. Intermediate the operating disc 24 and worm gear 2!] is a driven spider 25, towhich is keyed thefeed pinion shaft 22 for unison rotation therewith. Carried by the spider 25 are a pair of friction shoes 26 each pivotally mounted at 26. to a link 21; which in turn is pivoted at 28 'to the spider 25. Projecting from the outer side of the operating disc 24 isa' hub or hollow shaft29 to which either manual or, in this instance, automatic actuating ,means is applied to. produce fast travel motion of the quill I' I independently of the regulated spindle feed controlled by the secondary speedchangemechanism I2. Carriedupon thein'ner side of the operating disc, 24 are a pair of spring biased plungers 330' which under certain .operating conditions engage the links 21. Under, other'conditions of operationa pair of rollers'3l, also carried upon the inner sideof'theoperating disc 24, engage tail portions 32 of the links '21. The operating disc '24 'is also operativ'ely connected with the spider 25 through a lost motion connection comprising an enlarged hole '33 through which the pivot pin 28 projects. The operating portions of the clutch are all enclosed within the worm gear 2II'to which is'affixed a face plate 34.

t In operation", the worm gear 20 is continuously driven at a constant predetermined speed, governed by'the secondary speed change mechanism I2. When such speed is less than that of the operating disc 24, the gear 25 turns idly about the feed'pinion shaft 22. Under theseconditions the operating disc 24 is rotating faster than the worm gear'2Il and the pivot pin 28. engages the trailing edge of the enlarged hole 33 to drive the spider 25 and the associated feed pinion shaft'22 at an increased rate of speed. During this period the spring biased plun'gers 30 with their springs 35 compressed engage the adjacent edge of the links 21, tending to swing the links in a counterclockwise direction about their pivots 28. Such movement of the'links 21, however, is prevented inasmuch as the center pivot 28 of the toggle mechanism 2528 and feed pinion shaft 22 is being continuously moved forward, preventing li nme aq ili are 955 te Win terruption. or slowing of; the forward motion. of the operating disc; 24:, the: spring biased plungers are then able to. exert. their influence upon the links; 21 since. the center pivot:v 2:8. of? the toggle is free to, move. toward. dead. center position: in re-. lation. with the other pivots 2.6,. and the. feed pinion shaft. 22.

Such movement of the links. 27. brings the friction shoes 26' into. engagement with. the inside surface. of the. worm gear. 25. which is rotating at its predetermined. speed The speed, of the worm gear 2.6. being now faster than thespeed' of the operating disc 24, the friction shoes 26, become positively en aged therewith. Throu h the togglemechanism sufiicient: pressure is. produced toprevent. slippage ofv the shoes upon the; inner surfaceof the. worm ear 20,. Thus. thro h he friction shoes 26.13119. worm ear 21.0 rotates; he spider 25: and its associated feed; pinion. shaft. 2-2 at. the predetermined rate of..- speed.

Upon reverse rotation of: the operating disc 2,4 thev rollers. 3| carried thereby engage the; tail portions. 32: of the. links 21,. causing; he: links to rotate in a. clockwise direction. thereby disengaging the friction shoes 21c. from. the inner surface oi'the worm; gear 2.6;. The. feed. pin-ion, shaft- 22 is thereby again. disengaged: from the; positive control. or the worm ear; 201 and; placed under control. of. the. operating disc. 2,4; The reverse rotation of the. operating c 24. is.v tran mitted tothe; spider; 25 and associated feed; pinion shaft 22 throu h the pivot; pins 28.: which. now. en a the opposite. edge: ofthe. hole 33.

Carried upon the feed pinion. shaft; 2;2, is a. iced pinion. 3.6, the. rotary motiomoi which; is, trans.- lated. into.- vertical. reciprocatory motion; Qfi the quill. lrlzloy rack teeth 3;"! upon,thequillwith. which the; pinion 3.6; meshes.

By this arrangement theouill. l1. and drill spin dle: l hmai be rapidly moved; up ordown permitting' a rapid traverse of: the. non-producing portions of theoperating: cycle; whil maintaining a. fixed rate; of; feed in: relation to; the speed of the. drill; spindle. H: during the work producing portion; of the-operating cycle.

In; place of theusual handlever; normally used tocontrol therapid traverse-of the quill. inimane ally operated. machines; he: present. rill: pr employs: a power operated means, Secured, to the outerside of. the clutch housing; lafifisanr ad.- ditionalrhousing 3.8 which Servesas. a. sunport for a reversible torque motor 39,; theaxis, of;,which,is transversely: disposed. relative to .the feed. pinion shaftZZ: Driven by-the torque motor through a resilient,- coupling 40: is: a worm shait: 4:1 on the forward end of which a. hand: wheel 42 projects from the housing 38:. Secured to. the. shaft: 4 is a: worm. 4'3 which. meshes with a worm. gear 4.4 carried by the extended hub 29.. of the operating disc 24 of i the free: Wheeling: clutch. previously described. The. torque, motor; 3.5;; providesthe necessary power for rapidtraverse movements of" the drill spindle I I in. either directiorrand is of such construction that it may-berslowed or stalled indefinitelywithout becoming: overheated.

Under influenceiofi the-torque motor 39rthe. operating disc of theclutchll' causes a fast. ad'- vance or rapid. traverseof: the spindle l I untilthe spindle meets resistance to. its.- advance. on down.- wardmovement; Anyresistance encountered by the spindle It inv its; advance causes. a reduction in. speedofi the operating: disc Mitoan amount less: than the speed of the worm gearlflaresuitingin the: engagementiof theclutoh 2-;l with the woringear 20; 'Ihisv places theispindle lzl .under 'drum enclosing the end of the shaft 22.

control. of: the regulated. feed; asdetermined by thesecondary speed-change mechanism l2. During the: period of regulated feed the torque motor 39. rotates atthe. same speed. due. to the. braking effect thereon of the. clutch engaged. worm gear 20. Uponreversing. the. direction of rotation of thetorque motor 39,. the operating disc 2.4.reverses its. direction. of rotation, and therollers 3| carried thereby disengage the clutch. 21 from thewormgear 20. This permits. the. torque motor 39to again assume: control of the. feed pinion shaft. 22, producinga rapid traverse or fast re;- traction of the quill spindle. H from. the work piece.

In order to. artificially create resistancev to. the downward movement. of the drill spindle l;l. prior to thetimeitzengages the. workpiece an electromagnetically actuated brake upon the. feed pinion shaft 22 is. used. Secured to the outboard end'of'the feed pinion shaftzladjacentthe feed pinion 3G is a brake drum 45 keyed to the. shaft 22 for; unison rotation therewith. A cover plate 46. is secured to the outer surface of the: brake Surrounding the periphery of. the .brake drum 45.1153. relatively resilient. brake band one. end. of which is positively anchored at datothesupporting arm i5. The opposite end. 49. of the brake band is adjustable toward and from. the anchor 45 to engage and disengage the brake band. and the brake drum. Thebrakeband: is. adjusted by a toggle lever comprising. a link 56. to whichthe adjustable end 49 of: the brake band is, secured, and a link 5| one end of which is. pivotally anchored at 52 to the supporting. arm l5, the other 7 end being pivotally connectedat 53110 the link 58.

v the quill To engage the brakeband ll withtha drum t5, the pivot 53" which. is normally somewhat above dead center relative to,- the points 49 and 52,. is brought into substantially dead center relation therewith. This isaccomplished-v by means of: a bellcrank lever 54. pivotally secured at 55 to the supporting arm 15;. the;upper end 56 of whichjis pivotally secured to. the. solenoid 51.. The other end 54' of the bell crank l'everispivotally interconnected with the pivot point 53. by the connecting link 58. Thus when the solenoid is. energized, the lever 54 is: rocked in a clockwisediirection about its pivot 55. which istranslated into. a. vertical pull upon the. pivot; 53,1 of the toggle mechanism by the connecting. link 58 Actuation of the brake band.- ll: by. the solenoid 5'5. creates sufiicient resistance to-rotation of the feed pinion shaft 22 to cause the clutch 21' to engage the wormigear 2a, placingv the feed pinion shaft under control of the secondary speed change mechanism. It producing the predetermined regulated rate of feed of the quill. ll and drill spindle ii. Ifhe brake hand ll does not however create sufficient rotational resistance to. prevent operationof the feedpin-ion shaft 22 under the influence of the; regulated feed produced bythe secondary speed changemechanism I2... During theperiod of regulated feed-operationv the, brake band 4t merely: slips upon the brake drum 45..

Thev mechanism for. automatically controlling the reciprocatorymotion; of. the drill spindle H and-quill I! is contained within the-housing l4 supported upon the arm [5. Fixed to the-top of I! for unison reciprocatory, motiontherewith is a collar. Bil. Carried by the collar in spacedv relationwiththe front of the quill I? are a; pair. of. oppositely projecting arms 6| and 62 Io; the; arm.:..6 l: ther.e issecured; asni le r turn switch 63 which when closed actuates a mechanically held contactor 82 to energize the torque motor 39 in reverse direction to retract the spindle I l to its upper limit of travel. The point at which the return switch 63 is closed varies with each succeeding penetration of the spindle ll until a complete cycle of operation has been completed. The point at which the switch 63 energizes the torque motor 39 is determined by a solenoid operated tripping device comprising a sliding depth gage 54 mounted for reciprocatory motion upon a rod 65 fixedly supported at its upper and lower extremities in the walls of the housing M. This rod 65 is parallel with the spindle II, but both latterally and forwardly offset relative thereto. The depth gage 64 determines the depth of penetration of each successive drill feed operation, and is automatically lowered upon the rod 65 at the completion of each drill feed operation preparatory for the next such operation.

'To maintain the depth gage 64 in a predetermined position upon the rod 65 for each succeeding drill feed operation, the rod is provided with a ratchet like templet 6B, the distance between the teeth 91 thereofbeing equal to the desired penetration for each drill feed operation. The spacing of the teeth may be uniform, or may be varied with a greater spacing at the upper end to permit agreater penetration of the drill at the beginning of the operation, becoming shorter as the depth of the hole increases with more chip and coolant difficulties. The distances between the teeth are generally about equal to the diameter of the drill being used.

engage the flanges T9 of the templet sections.

When assembled the teeth 6! of the templets which project from the surface of the flanges Iii lie within the slot II in the bar 65. The vertical location of the templets relative to the rod 65 is maintained by the use of spacers 12. The lowermost spacer is held in adjusted position by a set screw 13 threaded through the wall of the housing l9 into engagement therewith.

Carried by the depth gage 64 is a pawl 14 which cooperates with the teeth 61 of the templets to maintain the gage in a predetermined adjusted position. The pawl M is periodically moved out of engagement with the teeth '61 by momentarily energizing a solenoid 15 carried upon the gage 54. Such movement of the pawl 14 permits the gage to drop down the rod 65 the distance to the next succeeding tooth into which the pawl is urged under-influence of the spring 16 about the rock shaft 11 upon which the pawl is mounted. By this means the gage is indexed downwardly on the rod 65 by predetermined increments, each increment being equal to the depth to be drilled during that portion of the operating cycle.

Rotational movement of the depth gage 64 upon the rod 65 is prevented by a dog screw 18 the end of which rides in the slot I9 in the back of the rod 65. A shoulder 89 is provided upon' the back of the gage 64 to engage the actuating member 8| of the spindle return switch 63. Actuation of the member 8| upon engagement 1 rod 94 is-supported within thehousing. in a 8 with the shoulder closes the switch 63 which simultaneously energizes the gage solenoid l5 and actuates the mechanically held contactor 82 to energize the torque motor 39 in reverse direction. Energization of the solenoid is momentary since the gage immediately drops to its next position as determined by engagement of the pawl with the next succeeding tooth. The shoulder 80 of the gage being moved away from the actuating member 8| of the switch, the switch is returned to its normally open position.

The torque motor 39 remains energized in re verse direction and raises the spindle H to its upper limit of travel motion. Upon reaching such upper limit, the torque motor is then again reversed to advance or lower the spindle .to drilling position. Actuation of reversing contactor 82 to change the direction of rotation of the torque motor is controlled by a switch 83 depending from the top surface of the housing |4.- The actuating member 84 thereof is engaged by a tail portion 85 of a latch piece 86 pivotally carried upon the arm iii. The latch 86 is spring biased in a clockwise direction by th spring 8! and plunger 88 supported within the arm 6|. Under normal operating conditions the latch is maintained in its spring biased position.

The final drilling operation is determined b the location of a final depth stop 89 comprising a split collar which is clamped in adjusted position upon the bar 65 by means of a screw 99. Rotation or" the stop collar relative to the rod 65 is prevented by engagement of a .dog screw 9i within the guide slot 79 in the back of the rod. Secured to the stop 89 in the path of travel of the latch 86 is a leaf spring 92. As the latch 86 contacts the leaf spring, it is rotated about its pivot into engagement with an undercut notch 93 in the bottom surface of the gage 64. The gage having completed its downward travel motion, is supported in the last tooth 61 adjacent the stop collar 89 in position to receive the latch 86 when pushed therein by the spring 92. This position of the depth gage 64 signifies the completion of the last drilling operation of the cycle. Upon subsequent closing of the spindle return switch 53, the spindle l l and quill II are retracted to their upper 'limit of travel motion, and by means of the latch 86 which moves in unison with the quill H, the gage 64 is also lifted to the top of the rod 65 preparatory to the beginningof a new cycle of operation.

The latch 86 having been moved in a counterclockwise direction into the notch 93, it is held in such position by the weight of the depth gage 64 until subsequent relaxation of the gages weight thereon. While held in its rotated posi-.- tion, the tail portion 85 thereof is swung out of alignment with the actuating member 84 of the spindle advance switch 83. Thus the spindle and quill, after the last retraction is held in retracted position by the torque motor 39 until the spindle advance switch 83 is manually closed to start a new cycle of operation.

As previously explained, the vertical travel speed of the quill, as determined by the torque motor 39 and the secondary speed ch'angemechanism I2, is regulated by energization of the brake solenoid 5'! and actuation of the brake. Energization of the brake solenoid is in timed relation with the energization of the gage solenoid l5 and the spindle return switch 63.- To provide for the timed relation between the energization of the various controls, anotherguide 1 plane parallel with, but forwardly offset relative to the spindle and quill IL: The guide rods 65 and 94 are located opposite laterally offset planes relative to the spindle and quill.

Carried near theouter end of the arm 92 which projects from the "collar 99 isia ,normal-lyopen 'b'rakeswitch 95, theclosing. ofwhich energizes the brake solenoid 51.. The switchis closed upon engagement of its actuating member 99 with a brake switch tripping device slidinglysupported The tripping. device 9? comprisesia pair ofcollars Ill! and 92, each of which is counterbored at their inner ends, to receive a i compression spring I93. The :lower collar I02 carries asst screw I04, the inner end of. which projects withinthe guide slot I95 in the rod 94. On the'op- .posite side of the collar. isa vertical hole I96, tapped toreceive the end of an adjusting bolt Ill'l 'which transfixes the upper collar lIlll-eThis bolt I91 maintains a fixed maximum spacing intermediate the .collars- IOI and IIJL. A'proj'ection I98 upon the upper collar IIll extends into the path of travel of the'swi'tch actuating member 96, which upon engagement --thei'ewith closes the brake switch 95 and bymeans ofythe solenoid 5? actuates: thebr'ake 47; The compression spring 03 has sufficient tensionto cause operation .of the switch actuating member 96 Without collapsing. Simultaneously with the operation of the switch actuating member 95, the projecting end of. the screw lsllengages-i the top of. the upper collar llll, thereby relieving'th'e switch; actuating member 99 "of. excessive pressure as the quill I1 and associated collar 69 descend under the control of the secondary speed "change mechanism The pressure screw I94 in thelower collar I92 creates sufficient resistance to movement to prevent the lower collar I92 from-sliding downwardlyunder the weight of the tripping device,

or-under the pressure exerted by the switch actu ating member 96. The frictional resistance of the lower collar is also sufii'cient to permit the collapsing of the sprin I93 under the downward pressure exerted by the screw: I99 upon the top surface of the upper collar Ifil Upon collapsing of the spring -I 93, the gap intermediate the upper and lower collars lIll and'192' is closed, the upper collar llll bearing directly upon the lower collar IUZ. The frictional resistance of the lower collar. 192 is not. suficient to withstand this condition, resulting in a downward movement of the entire tripping device"9|'"under the pressure created by the downward movement of'the' quill i I as transferredtnrougn'the arm- 62 and screw" its to the uppercollanllll of the tripping'devicef Upon completion of the particular drill feed operation and the retraction-'of the spindle Il', .thet lower collar I92 of the tripping device re mains in itsgnewly adjusted positicn, such posia tion representing-the actual depth of the drihed hole in the workpiece;- As thespindle H and -'q'uill 'l I are retractedto their upper limit of travel motion, pressure upon the uppercoinr-ie'e 'is relieved, permitting the: compression spring Hi3 9,221,111 expand and'i als the upp'er cciiac la! to its maximum-height relativeto the lower colpreviously drilled hole in the work piece. Actuation of the brake causes the downward motion of the spindle to change-from rapid traverse movement under control-of, the torque motor 39 to the regulated drill feed under control of the I secondary speed change mechanism lzi This change in spindle feed takes place-just before the drill engagesthe bottom of the hole as drilled in the work piece'during the-preceding portion of thecyclef H A final step 599 comprising a split collar similar to thestop collar 89 is adjustably supported upon the rod 94 by means of a screw H9. Afiixed to the stop collar 199 is a leaf spring III which projects upwardly into the path of travel of the latch member 99. Upon completion of the last drill feed operation-as determined by the loca tion of the stop 89, the tripping device 9'! will have been pushed downwardly upon the rod 94 into engagement with the stop collar I99 by the arrn ez and screw Hi9; At this point, the leaf spring II I urges the latch 99; into engagement with the re-entrant notch I l2 on the upper collar I. Upon the final retraction ofthe quill ll and arm 62 to complete the cycle of operation,

the tripping device 9l will be moved upwardly on the rod 94 preparatory to the starting of a new cycle of operation;

; Adjustably secured inthe top of'the housing 14 .is a depending latch trip rod H3 which returns the latch 98 to its normal position thereby releasing the tripping device 9'l. Thelatch 98 having been swung in a counterclockwise direction by the leaf spring I I I, the tail portion l I4 of'the latch projects beneath the end of the trip rod H3. As the latch is raised the tail portion H9 7 engages the end of the trip rod Hand is returned to its normal vertical position by the cam surface H5. When this occurs, the latch is disengaged from the notch IIZ of the tripping device 97 leaving the tripping device in its adjusted position upon the rod 94. The trip rod H3 is so adjusted by means of a set screw H3 that the engagement of the latch therewith occurs at a point corresponding to a slight elevation over 'and'above the top surface of, the work piece.

By such adjustment, the brake switch is closed to energize the brake and change the spindle travel from rapid traverse to regulated feed slightly before the drill en ages the Work piece.

During the final retraction of the drill, both 'the'tripping device'fil and the depth gage are elevated from their lowermost positions and are left in position to control'the initial operation of the next succeeding cycle.

Attached to the machine at some point within convenient reach of the operator is a four button push button control station H9 (Fig. 10), When necessary, complete manual control of the machine'is obtained throughthe use of these four push buttons. 1

Connectedto the power lines is" an electromagnetic across the line motor starter l I1 of Which there are severai makes readily obtainable upon the open market. The starter magnet is .energized by depressing the start button I I8. In-

ternal wiring within the starter II'I provides a holding circuit for the magnet after it is once energized by the momentary closing of the button I I8. The circuit to the main motor 6 is then completed through wires II8, I20, and I2I. Connected in parallel with the main motor 6 by means of wires I22, I23, and I24 is the mechanically held reversing contactor 82 to which the torque motor 39 is directly connected. The direction of rotation of the torque motor 39 is controlled by the selective energization of the advance coil I25 or the return coil I26 in the re versing contactor 82. Also connected through the magnetic starter H1 is a transformer I21, the output of which is supplied to the several control "circuits.

After locating the work piece to be drilled, the operator momentarily closes the start button II8 which energizes all of the high voltage circuits. The main motor 6 is thereby put in operation, which through the primary change speed mechanism 9 rotates the spindle II at a preselected speed. Closing'of the start button II8 also energizesthe torque motor 39, its direction of rotation being such as to elevate the spindle II inasmuch as the return or up coil I26 was last energized for completion of the preceding cycle of operation.

To initiate or start the cycle of operation, the operator momentarily depresses a down button I28 which completes a circuit from the transformer I21 through wire I29, switch terminals I3Il--I3 I, wire I32, to the advance or down coil I25 of the contactor 82. The opposite terminal I33 of the coil I25 is connected by Wire I34 with the transformer I21 to complete the energizing circuit. I V y The torque motor 39being now energized in advance or down direction, the spindle I I is advanced toward the work piece at relatively high speed until the brake switch 95 traveling downwardly in unison with the spindle II, contacts the brake tripping device 91. Closing of the switch 95 sets the brake 41 by energization of the brake solenoid 51 through a circuit from the transformer I21. Currentis supplied by the transformer I21 through wire I29, contact I38, jumper wire I35 to contact I36 of the manually controlled spindle return or up switch I 31. From the contact I36, wire I38 leads to the brake solenoid 51 from where the circuit is completed by wire I39, switch 95, wire I49, contacts I4II4I in the reversing contactor 82 which are bridged by the contactor when in the advance or down direction, wire I42, contact I33 of theadvance coil I25 and wire I34 to the transformer I21.

Upon application of the brake 41, continued downward movement of the spindle II is placed under the control of the secondary speed change mechanism I2. The spindle having completed a rapid traverse of the un-productive portion of its travel motion, it i now advanced or lowered at the pre-determined speed of the regulated drill feed.

During such initial downward movement of the spindle the depth gage 64 is lowered in unison therewith, the gage still being supported upon the latch 86. The unison downward movement of the spindle and depth gage continues until pawl 14 enters the first tooth 61 on the rod 65, whereupon continued downward movement of the gage 64 is arrested. Spindle II, however, continues its downward movement at the reduced spe 94 the former I21.

12 regulated drill feed until the actuator 8I of return switch 63 engages the shoulder 89 on the gage 64. During this time the latch 86 swings outwardly -(in aclockwise direction) underin- 'fluence of its biasing spring upon release thereof by relaxation of the gages weight thereon. Upon contacting the shoulder 88, the return switch 63 is momentarily closed to simultaneously reverse the contactor 82 and energize the solenoid 15. Current is supplied to the return coil I26 of the contactor 82 by the transformer I21, wire I29, contact I39 of the switch I28, wire I35, contact I36 of switch I31, wire I43, switch 63,'wire I44,'contact I45 of switch I31, and wire.I46. The circuit is completed from the return coil I26 to the transformer I 21 by wire I41; contact I33 of the advance coil I25, and wire I34. Energization of return coil I26 of contactor 82 reverses the direction of rotation of the torque motor 39, to return or elevate the spindle II to its uppermost or original starting position.

' In parallel Withthe return coil I26 is the solenoid 15, which upon 'closing of the switch 63is also energized by the transformer I21. The solenoid circuit extends from the transformer I21 through wire I29, contact I38 of switch I28, wire I35, contact I36 of switch I31, wire I43, switch 63, wire I44, contact I45wire I44, contacts I45- I36 of switch I31, and wire I 48 to the solenoid 15. From the solenoid the circuit is completed through wire I48 to the transformer I21. Energization of the solenoid 15 withdraws the pawl 14 from the teeth 61, permitting the depth gage 64 to drop to the next succeeding tooth 61 with which the pawl 14 is re-engaged to retain the gage 64 in position for the next succeeding portion of the operating cycle.

The spindle travel being reversed upon closing of the switch 63,-the spindle is elevated or retracted until it reaches its upper'limit. Upon approaching its upper .limit, the tail portion of the latch 86 engages the actuating member 84 of the spindle advance switch 83 secured to. the upper surface of the housing I4. Closing ofthe advance switch 83 energizes the advance coil I25 of the contactor 82 thereby reversing the direction of rotation of the torque motor 39, which thereupon lowers or advances the spindle II by rapid traverse into proximate relation with the work piece, the rapid traverse of the spindle being terminated by the closing of the brake switch 95.

Closing of the advance switch 83 completes a circuit to the advance coil I25 from the transformer I21 by wire I29, contact I38 of switch I28, wire I49, switch 83, wire I58, contact I3I of switch I28, and wire I32. The return side of the circuit is completed from contact I33 of theadvance coil I25 through wire I34 to the trans- The automatically operated spindle advance or down switch 83 is in parallel with the manually controlled down switch I28.. The manually controlled up switch I31 is in a parallel circuit-with the automatically operated spindle return or up" switch 63 insofar as control of the reversing contactor 82 is involved. The manual switch I31 does not however control energization of the gage solenoid 15. The gage 64 must be retained in its automatically adjusted position if the machine is to be returned to automatic operation; If the solenoid 15 were manually energized by depression of-the up switch I31, the gage 64 would be dropped to the final stop 89 and the spindle would continue its next downward movement until it reached the equivalent: of the finalv drilling operation without the necessary retractions for cooling and chip clearance. For'thisreason the control circuit is so arranged that the gage :54 remains in its automaticall adjusted position notwithstanding manual control of the spindle by depression of the upbutton I31. The gage 54 and its control solenoid 15 are actuated onlyupon closingof the spindle return switch 63. "Thus should it be necessary or desirable to reverse the direction of the spindle travel prior-to the time of automatic'reversal thereof, such a change may be accomplished manually by depressing the appropriate manually controlled switch.

After completion of the drillingopera'tion, the spindle II is returned to its uppermost position, and with this last retraction of the spindle the depthgage fi l and brake tripping device 91 are raised the brake-tripping device being left in position for the first operation of the next cycle. The latch'86 being engaged with the depth gage 64 during this final 'upward'movement, the tail portion 851s swung out of line relative to the actuating member or" the advance switch 83. The advance switch 83 istherefore not closed, and

the torque motorremains energized in the up or "it's uppermost limit of travel.

The spindle remains in this position while the finished work piece is being removed and a new work piece is being inserted in the machine. After insertion of the new WOIk piece, a new cycle of operation is commenced by the manual depression'of the down button I28 as previously described; f v I Should the completion or the drilling operation on the work piece coincide with completion of the days work, or for any other reason, the next'opcrating cycle is not to beiminediately started, the motors 6 and 39 are die-energized by depression of the stop button I5I. Opening of the switch I 5I de' energizes the holding circuit of the magnetic contactor II1, thereby opening the main power supply line to the" machine. The start and stop buttons II 8 and I5 I, respectively, control the conreturri direction, thereby holding the spindle at tactor II! through the wires I52, I 53, and I54,

wire I52 being common to both buttons. 1 The start circuit comprises wires I52 and I 53, while the stop circuit consists of wires I52 andv I54.

Not only 'doesa machine of the type described herein represent a reduction in the initial cost as or less specificsas tc structural features; it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise the preferred formof several modes of putting the invention into effect, and the invention is therefore claimed in anyof its forms or modifications within the legitimate and valid. scope of the appended claims. a i

Having thus described my invention, 1 claim:

1. An electrically operated drill press of the automatic step-drilljtype wherein an operating cycle consists of a series of alternate up and down movements of the drill spindle and tool out of and into a work piece including means for automatically controlling the reciprocations of the drill spindle and arresting motion of the spindle at the completion ofan operating'cycle, comprising a fixed electrical'switch relative to which the spindle reciprocates, a pair of travel- I in'g electrical switches mounted on the spindle compared withmachine employing hydraulic controls, but it hasfar greater accuracy and dependability. The controls for the present machineare not subject tovariation due to change in temperature, nor'are they dependent upon the continued maintenance of a predetermined fixed pressure. Once adjusted, the present controls will repeatedly operate at the identicalrpoint, aifording almost instantaneous response in the machineoperation. Once a particular job is set up on the machine, the settings may be'duplisated atany time in the future when it becomes necessary to run the same job again. Theresetting of the controls is accomplished, without the necessity of step-by-step adjustments s thereof.

The-machine is adaptable for many different types ofdrill operations under varying conditions, its flexibility being in no way sacrificed for its positiveness of action, and simplicity of construction and operation; r

While the control system has been described in :connectionwith its application to a drill press, it is equally applicable to other types of machine tools having a reciprocatory tool memberv movfor unison travel motion therewith, a pair of traveling stops adjustably mounted uponthe arm press relative to which the spindle reciprocates,

means for automatically adjusting said stops upon engagement of the traveling switches there-'- with, one of said stops being adjusted in unison with the downward movement of the spindle, the other of said stops'being adjusted to a predetermined position independentlyof the travel movement of the spindle, means 'for retarding the downward movement of the spindle upon engagement of one of said traveling switches with one of said stops, means for reversing the travel motion of the spindle upon engagement of the other of said traveling switches with the other of' said stops, oscillatory means carried by the spindle normally'engaging the fixed switch to reverse the direction of'the spindle at its upper limit of travel motion, a second pair of stops fixed in predetermined adjusted position relative to i which the spindlereciprocates, means actuated by the approach ofthe traveling switches to the second-pair of stops for interconnecting the traveling stops with thespindle for unison upward movement therewith, and simultaneously moving said oscillatory means out of the path of the fixed switch thereby stopping the spindle at its upper limit of travel motion, and means for releasing, the traveling stops from the 'spindle'in predetermined positions preparatory to the starting of anew cycle of operation.

2. In a drill press of the automatic step-drill type wherein an operating cycle comprises a series of reciprocatory movements of thedrill spindle and tool into and out of'a work piece during which cyolethe drill spindle has alternate pee riods of fast and slow vertical travel motion, an electrical-operating system therefor including a reversible torque motor intermittently energized inalternate directions toraise and lower the spindle during periods of relatively fast'travel motion, a continually: energized uni-directional drive motor intermittently connected to the drill spindle to lower said spindle at a relatively slow uniform rate of speed, an electrically controlled clutch alternately subjecting the spindle to the influence of-the torque motor and the uni-directional drive motor, and energizing means for the electrically controlled clutch comprising an electrical switch, a laterally projecting arm carried by the spindle upon WhlCh'1l7h8 switch is mounted, a vertically expansible switch tripping device, a stationary supporting rod therefor relative'to which the spindle reciprocates and upon which the tripping device is vertically adjustable by engagement/cf the laterally'projecting arm therewith, the construction and arrangement being such that uponcontact of the switch with the tripping device the electrically controlled clutch is energized subjecting the spindle to the con-' trol' of the uni-directional: drive; motor to lower the spindle at therelatively, slow uniform rate of speed and simultaneously .therewith compress and lower the tripping device by the engagement of the laterally projecting; arm therewith.

3. In a drill press of the automatic step-drill type wherein an operating cycle comprises a series of reciprocatory movements of the drill spindle and tool into and out of a workpiece, a control system therefor including power means for lowering the spindle at a relatively high rate of speed during the initial portion of its downward movement, additional power means for lowering' the spindle at a relatively low uniform speed, the rate of which isfixed relative to its speed of rotation, electrically controlled means alternately subjecting the spindle to the control of the first and second power means, electrically controlled means responsive to movement of the spindlefor reversing the first power means to retract and advance the spindle at the relatively high rate of speed, means for energizing therespective electrical control means com prising a plurality of bodily movable electrical switches one for each of said control means, and a plurality of bodily movable tripping devices with which the switches cooperate, means for moving the tripping devices and switches in accordance with the movement of the drill spindle and tool relative to the Work piece to thereby control the reciprocatory movements of the spindle and tool, and stop means adjustably determining the completion of the operating cycle.

4.,In a drill press of the automatic step-drill type wherein an operating cycle comprises a series of reciprocatory movements of the drill spindle and tool into and out of a Work piece, a control means including a reversible torque motor operative to raise or lower the spindle at a relatively high rate of speed, a conventional drive motor operative to lower the spindle at a relatively low uniform speed, a clutch alternately interconnecting th spindle with the torque motor and the conventional motor, electrically controlled means for actuating .the clutch, electrically controlled means for reversing the torque motor in optionally timed relation with the actuation of the clutch, a plurality of switches fixedly carried upon the spindle for intermittently energizing the electrically controlled means, a plurality of vertically adjustable gages cooperating with the switches to actuate said switches, means carried bythe drill spindle for adjusting said gages downwardly in accordance with the movement of the tool into the work piece, a third switch fixedly mounted upon the drillpress relative to which the spindle reciprocates for energize ing the electrically controlled reversing means for the torque motor in predetermined relation with'the 'energization of the reversing means by one of the plurality of switches, and vertically adjustable stop means determining completion of the operating cycle including means for detachably engaging said gages with the spindle for return movement to their initial position;

5.-In adrill press of the automatic step-drill type wherein an operating cycle comprises a series of reciprocatory movements of the drill spindle and tool into and out of a work piece during which cycle the drill spindle has alternate periods of fast and slow vertical travel motion, an electrical control system therefore including a first power means for vertically actuating the spindle during its period of fast travel motion, a second power means for actuating the spindle during its period of slow travel motion,- electrically operated means controllingactuation of the spindle by the first or second power means, and means for energizing the electrically operated control means comprising a laterally projecting arm carried by the spindle, a switchsupported thereon for unison travel motion with the spindle, and means for actuating the switch at predetermined intervals including a stationary guide rod, the axis of which is parallel to-the spindle and relative to which the spindle reciprocates, a two piece expansible and contractible sleeve frictionally engaged therewith, an expansion spring intermediate the two parts of the sleeve against the tension of which the .sleeve is compressible upon engagement ofthe switch and laterally projecting arm therewith, the construction and arrangement being such that pressure of the arm upon the sleeve overcomes the friction thereof and lowers the sleeve in unison with the spindle, and means for limiting the expansion of the sleeve upon removalof pressure therefrom.

6; In a drill press wherein an operating cycle comprises a series of vertical reciprocatory movements of the drill spindle and tool into and out of a work piece, and automatically adjustable depth gage therefor including a vertically adjustable gage member, a support therefor the axis of which is parallel with the drill spindle and with which the gage member has sliding engagement, a re-entrant longitudinally disposed groove therein, a series of differentially spaced ratchet teeth removably engageable therein, a spring tensioned pawl pivotally supported upon the gage member for tensioned'engagement with the respective ratchet teeth, electrically operated means for withdrawing the pawl from the ratchet teeth to permit the gage member to move downwardly upon the support until arrested by engagement of the pawl with the succeeding downwardly spaced ratchet tooth, and means for energizing the electricallyiopen ated means in predetermined relation to the spindle position comprising an arm carried by the spindle for unison travel motion therewith, and projecting laterally in overhanging relation with the gage member, a switch fixedly attached to-the arm, and means engageable with the gage member upon contact of the arm therewith for actuating the switch, the construction and arrangement being such that actuation of the switch energizes the electrically operated pawl control means.

'7. In a machine tool having a predetermined cycle of operation, a reciprocatory tool member, means for determining the extent of reciprocatory movement of the tool member comprising an adjustable gage member, a ratchet bar upon which the gage member is slidingly adjustable, the ratchet teeth of said bar being difierentially spaced in predetermined relation, means for interchanging the ratchet teeth for others of different spacing, a detent on the gage member cooperating with the ratchet teeth to retain the gage member in progressively changing predetermined position upon the bar, electrically operated actuating means for the detent, means actuated by the reciprocatory movement of the tool member for energizing the detent actuating means, the construction and arrangement being such that the gage member is progressively moved along the bar by a step by step movement in accordance with the spacing of the ratchet teeth therein, and means for determining the completion of an operating cycle and simultaneously therewith returning the gage member to its initial position.

ROBERT H. ALLEN.

5 REFERENCES CITED The following references are of record in the file of this patent:

0 UNITED STATES PATENTS Number Name Date 1,911,138 Clute et al. May 23, 1933 2,035,283 Schroeder Mar. 24, 1936 2,053,398 'Kingsbury Sept. 8, 1936 15 2,053,399 Kingsbury Sept. 8, 1936 2,260,327 McKee Oct. 28, 1941 2,324,727 Shartle July 20, 1943 

